Patent Literature 1 describes an example of a brake actuator configured to apply brake force to a wheel in accordance with a rotary amount of an electric motor. A vehicle provided with such a brake actuator is provided with a rotary body (for example, disk rotor) configured to rotate integrally with the wheel and a friction member (for example, brake pad) to be pressed against the rotary body by force transferred from the brake actuator.
Further, Patent Literature 1 also describes that an electric motor is driven by an advance angle control (which is also called “field weakening control”). In this advance angle control, a magnetic flux in a d-axis direction is reduced to increase rotary speed of the electric motor by setting an excitation current value of a q-axis component to a value corresponding to torque to be generated by the electric motor and setting an excitation current value of a d-axis component to a negative value. Due to this, by performing such an advance angle control, a friction member quickly approaches a rotary body as compared to a case of performing a normal motor control that is not the advance angle control. As a result, a timing to start applying brake force to a wheel can be brought forward.